Slides in this set
States the brain of schizophrenics produces more
dopamine than normal brains.
· Evidence is from : studies with drugs
· post mortems
· pet scans
· Suggests an excess of dopamine receptors at
synapse contributes to schizophrenia,
· Phenothiazine drugs reduce symptoms of
schizophrenia. They block dopamine receptors so
schizophrenia may be due to an excess of
An increase in dopamine in the mesolimbic
pathway contributes to positive symptoms.
· An increase in dopamine in the mesocortical
pathway contributes to negative symptoms.
· Drugs that increase dopamine activity e.g.
Amphetamines make the symptoms worse which
is added evidence for a neurochemical cause.
· Large quantities lead to delusions and
· Some evidence shows that schizophrenics have
enlarged ventricles and smaller frontal lobes,
with higher incidence of head injury in childhood.
Any of these features link with prefrontal cortex
damage. The prefrontal cortex finishes
developing in adolescence.…read more
LINDSTROEM ET AL 1999 PET SCAN
· Radioactivity labelled a chemical IDOPA (used to
· Administered to 10 patients with schizophrenia
and 10 without
· IDOPA taken up quicker with schizophrenic
· Suggests schizophrenics were producing more
FALKAI ET AL 1988
· Autopsies have found that these with
schizophrenia have a larger than normal number
of dopamine receptors
· Concluded that dopamine production is abnormal
for schizophrenics.…read more
EVIDENCE THAT DOPAMINE IS INVOLVED IN THE
1. Genetic link with schizophrenia and dopamine production.
genes that are likely to increase sensitivity to dopamine
are found in these who develop schizophrenia.
2. Schizophrenics are more sensitive to dopamine update.
scanning shows that if schizophrenics given
amphetamines there is a greater release of dopamine
compared to normal people. Suggesting that
schizophrenics are more sensitive to the production.
3. Anti-psychotic drugs e.g. Phenothiazine block dopamine
receptors and reduce symptoms. less dopamine
produced when drugs taken which results in reduction of
schizophrenic symptoms.…read more